Question 1

A light ray strikes a flat mirror at an angle of incidence of $$30^\circ$$ with respect to the normal. What is the angle between the incident ray and the reflected ray?

Accepted Answer

$$90^\circ$$

Question 2

According to the law of reflection, which of the following statements is always true?

Accepted Answer

The angle of incidence equals the angle of reflection, both measured from the normal.

Question 3

If your height is $$h$$, what is the minimum height of a vertical plane mirror required for you to see your full image?

Accepted Answer

$$\frac{h}{2}$$

Question 4

A laser beam passes from air ($$n_1 = 1.00$) into water (n_2$ = 1.33) at an $$angle of incidence of $$45^\circ. $$Using Snell's Law, what is the angle of refraction in the water?

Accepted Answer

$$32^\circ$$

Question 5

Which of the following best explains why a fish in an aquarium sees a cat outside as being closer than it actually is?

Accepted Answer

Light rays bend toward the normal as they leave the water, making the cat appear closer.

Question 6

A ray of light travels from glass ($$n=1.50) $$into air ($$n=1.00). $$What is the critical angle for total internal reflection at the glass-air boundary?

Accepted Answer

$$41.8^\circ$$

Question 7

Which of the following statements about fiber optics is correct?

Accepted Answer

Total internal reflection keeps light trapped within the core of the fiber.

Question 8

A converging lens has a focal length of $$20\ \mathrm{cm}. An $$object is placed $$60\ \mathrm{cm}$$ from the lens. Where is the image formed?

Accepted Answer

$$30\ \mathrm{cm} on $$the opposite side of the lens

Question 9

Which of the following is true for a diverging lens?

Accepted Answer

It always forms a virtual, upright image.

Question 10

A 3.0-cm-high object is placed $$60\ \mathrm{cm}$$ from a concave mirror with a focal length of $$40\ \mathrm{cm}. $$What is the height of the image?

Accepted Answer

$$6.0\ \mathrm{cm}$$, inverted

Question 11

Which of the following best describes the image formed by a convex (diverging) mirror?

Accepted Answer

Virtual and smaller than the object

Question 12

A magnifying lens produces a virtual image with a magnification of $$+4$$ when the object is $$2.0\ \mathrm{cm}$$ from the lens. What is the focal length of the lens?

Accepted Answer

$$2.7\ \mathrm{cm}$$

Question 13

Which sign convention is correct for the focal length $$f in $$the thin-lens equation for a diverging lens?

Accepted Answer

$$f is $$negative

Question 14

A ray of light passes from water ($$n=1.33) $$into air ($$n=1.00) at an $$angle of incidence greater than the critical angle. What happens to the ray?

Accepted Answer

It is totally internally reflected.

Question 15

Which of the following is a correct application of Snell's Law?

Accepted Answer

$$n_1$$ \sin \$$theta_1$$ = $$n_2$$ \sin \$$theta_2$$

Question 16

A lens forms a real, inverted image that is twice as tall as the object. What is the magnification $$m$$ and the sign of the image distance $$s'$$?

Accepted Answer

$$m = -2$$, $$s' \u003e 0$$

Question 17

A ray of light passes from air into cubic zirconia ($$n=2.18). If $$the angle of incidence is $$20^\circ$$, what is the angle of refraction?

Accepted Answer

$$8.9^\circ$$

Question 18

Which of the following best explains why the passenger-side mirror on a car is convex?

Accepted Answer

It produces a smaller image, allowing a wider field of view.

Question 19

A diverging lens with a focal length of $$-50\ \mathrm{cm} is $$placed $$100\ \mathrm{cm}$$ from an object. Where is the image formed?

Accepted Answer

$$-33\ \mathrm{cm} on $$the same side as the object

Ray Optics: Reflection, Refraction, Lenses, and Mirrors

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